4-methylcatechol is a metabolite of homoprotocatechuic acid. It is both a substrate and a suicide inhibitor of Catechol 2,3-dioxygenase [EC 1.3.11.2]. (PMID 15006807 ). 4-methylcatechol is known to induce the production of brain-derived neurotrophic factor (BDNF). Recent studies have suggested that a lack of brain-derived neurotrophic factor (BDNF) in the limbic system may cause neuropathic pain. (PMID: 22198556 ).